Girls got excited while riding stallions, so it's not surprising that when they saw those guys they jumped on them. Well, their chosen pose is exactly what I pointed out in the previous sentence. It has always been a mystery why so many girls love horses, actually this video partially answers this question.
Sex with some stranger or new partner has its positives. It adds to the experience, even the thought of such a forbidden for many is arousing, counting on the stamina and imagination of the partner. Sex in the bar is somewhat relaxing and not as luscious as on the bed. This couple's anal sex and caresses deserve praise and encouragement.
She does it with her mouth and her pussy better.